At present, it needs to convey materials from a sterile space to another and maintain the sterile state in the process in non-sterile production environment of products in pharmacy, biology, food and other industries. Technical difficulty is huge in the event of sterile transfer of a great number (>10 kg) of sterile powder materials in a non-sterile environment.
Powder residue will be left on the inner surface of butterfly valve, including valve clack and seal ring, after powder conveying. The powder residue will disable sealing of butterfly valve to contaminate the sterile materials due to exposure to non-sterile environment. Meanwhile, the powder will leak into the environment, particularly some sensitive materials, to have negative influence on the environment and operating personnel. In addition, the cleaning media will leak into the materials during online cleaning to contaminate the sterility of materials to be transferred and receiving containers.
The technology widely used in the world is split butterfly valve technology, but it has some defects: a) powder residue will be left on the inner surface of butterfly valve after powder conveying to damage air-tightness of butterfly valve and sterility of products; b) the powder residue causes wear of sealing gasket of butterfly valve to leak fine particles, which entails frequency replacement of sealing gasket; c) online cleaning and sterilization between two split valve clacks is impossible due to unreliable sealing; d) VHP disinfection technology fails to strictly guarantee sterility; e) leakage is possible during VHP disinfection, bringing risk to health of production personnel. The sterility guarantee of this technology is insufficient as air-tightness can not be guaranteed.